Several industrial processes, such as a Selective Catalytic Reduction (SCR) system, a reboiler, and a demethanizer boiler of a gas plant, require a low temperature heating medium.
A pre-cooled gas turbine exhaust often is the source of the low temperature heating medium.
One known method of cooling the gas turbine exhaust is by spraying water into the exhaust gas. The supply of water into the gas turbine exhaust generally detrimentally affects the process due to the presence of water or steam within the low temperature heating medium as the dew point of the heating medium is lowered. Another drawback of this method is that water may be in short supply.
Another method of cooling the gas turbine exhaust is by introducing relatively cold dilution air to the exhaust gas. One of the disadvantages of this method is related to the added power consumption of the fans which introduce the relatively cold air into the exhaust gas. Another disadvantage is related to the increased fluid volume and the increased oxygen content of the heating medium which may detrimentally affect the process.